The present invention relates to improved Mg-Si type aluminum alloys, and in particular to compositions and methods for production of improved Mg-Si type alloys.
Mg-Si type aluminum alloys such as 6XXX series aluminum alloys are widely used and favored for their moderately high strength, low quench sensitivity, favorable forming characteristics and corrosion resistance. 6XXX series alloys are increasingly attractive to industries such as transportation because of these well-known properties. Additional applications for 6XXX series alloys would be possible if higher strength levels could be achieved. Preferably, these strength levels would be achievable with or without deformation and without any significant decrease in working properties.
Various elements have been added to Mg-Si type alloys to improve their properties. For example, U.S. Pat. No. 2,336,512 discloses an aluminum base alloy containing 1 to 15% Mg, 0.1 to 5% Cu, or from 2 to 14% Zn, or from 0.3 to 5% Si or combinations of these. In addition, the alloy may contain manganese, chromium, titanium, vanadium, molybdenum, tungsten, zirconium, uranium, nickel, boron and cobalt. Beryllium is added to prevent dross formation and magnesium losses.
Japanese application No. 57-160529 discloses a high strength, high toughness aluminum alloy containing 0.9 to 1.8% Si, 0.8 to 1.4% Mg, 0.4 to 1.8% Cu, and containing at least two of 0.05 to 0.8% Mn and 0.05 to 0.35% Cr.
U.S. Pat. No. 1,952,048 discloses an aluminum-beryllium alloy containing from 0.025 to 1.0% beryllium, 0.1 to 1.0% silicon, 0.1 to 0.5% magnesium and 0.1 to 6.0% copper having improved hardness and age hardening properties.
Japanese application No. 59-12244 discloses a method for manufacturing a high strength aluminum alloy conductor containing 0.5 to 1.4 wt. % magnesium, 0.5 to 1.4 wt. % silicon, 0.15 to 0.60 wt. % iron, 0.05 to 1.0 wt. % copper, 0.001 to 0.3 wt. % beryllium, the remainder aluminum.
U.S. Pat. No. 4,525,326 discloses an aluminum alloy for the manufacture of extruded products, the aluminum alloy containing 0.05 to 0.2% vanadium, manganese in a concentration equal to 1/4 to 2/3 of the iron concentration, 0.3 to 1.0% magnesium, 0.3 to 1.2% silicon, 0.1 to 0.5% iron, and up to 0.4% copper.
In spite of these references, there is still a great need for an improved aluminum base alloy having improved strength properties while maintaining high levels of elongation.